MassDOT Case Studies in Tidal Restoration...9 Culvert Replacement Benefits •Improve tidal flushing to the marsh –Improve salt marsh, reduce Phragmites –Improve quality of fishery

MassDOT Case Studies in Tidal RestorationCrescent Marsh - Saugus, MA

Bass River – Dennis, MA

September 11, 2018

Northeastern Transportation & Wildlife Conference

Susan McArthur, MassDOT HWY Environmental

Ryan Lizewski, VHB

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• What is tidal flow restoration?

• What are the benefits and why is it important?

• How do we do it?

Introduction

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Crescent Marsh Culvert Replacement - Saugus

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Crescent Marsh Culvert Replacement-Saugus

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Crescent Marsh Culvert Replacement-Saugus

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Crescent Marsh Culvert Replacement - SaugusVegetative

Community Area (SF)Percent

Coverage

Phragmites 550,092 56.6%

Salt Marsh 1,802 0.2%

Shrub-scrub 44,701 4.6%

Solidago 375,838 38.6%

Total 972,433 100.0%

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Culvert Replacement Benefits

• Improve tidal flushing to the marsh

– Improve salt marsh, reduce Phragmites

– Improve quality of fishery habitat

• Resiliency

– Increase culvert size from 48-inches to 6-foot by 6-foot box

– Reconnect Crescent Marsh with Bear Creek Estuary


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• No funds for project – How move forward?

– Added ~$2 million culvert replacement project to a nearby ~90+ million project.

Bundle PS&E into the nearby Belden Bly Bridge Project

– Used open services contract to develop project on accelerated schedule

• Needed to determined cost-effective replacement structure that would:

– meeting hydraulic performance standards

– Increase tidal flushing volumes to restore salt marsh

– provide greater resiliency to infrastructure in tidal environment.


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Permitting:

• Bridge Exempt Project

• 404 USACE PCN

• 401 Water Quality Certification

• MassDEP Bureau of Waste Prevention SW-45

• MassDEP Bureau of Waste Prevention SW-36


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HEC-RAS Model Framework

NFIP Flood Insurance Rate Map 14


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HEC-RAS Profile and Calibration

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Water Surface Elevation Results

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Tidal Flushing and Runoff Volume Results

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Culvert Design – Plan View

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Culvert Design – Phasing

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Bass River Rail Trail Bridge – Dennis -Yarmouth

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Bass River Bridge from early 1900’s, view to north

Bass River Bridge from 1990’s view to the south

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Pre-Existing Crossing

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Channel Widening Benefits

• Improve tidal flushing

– Reduce nutrient concentrations w/in upstream bay & pond (evaluated by USACE in 2013)

– Improve salt marsh, reduce Phragmites,

– Improve quality of fishery habitat

• Improve navigability

– Increase 60’ channel to ~114’ channel

– Reduce velocities, improving navigability through structure

– Mariners get better alignment when approaching Route 6 bridges


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Permitting

• 404 USACE Individual Permit

• USCG Section 9 Bridge Permit

• Coastal Zone Management Consistency Review

• Section 7 – NMFS, USFWS

• 401 Water Quality Certification (dredging and filling)

• Chapter 91 Waterways License

• MA Endangered Species Program

• Essential Fish Habitat Assessment

• MA Wetlands Protection Act (Dennis and Yarmouth)


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CCRT Crossing

HEC-RAS Profile

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CCRT Crossing

BFE 6-ft

BFE 6-ft

NFIP Flood Insurance Rate Map (July 3, 1984)

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CCRT Crossing

BFE 12-ft

BFE 9-ft

NFIP Flood Insurance Rate Map (July 16, 2014)

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Bridge Design – Plan View

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Bridge Design – Section View

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Thank you

Susan [email protected]

857-368-8807

Ryan [email protected]

617-607-2684

MassDOT Case Studies in Tidal Restoration

MassDOT Case Studies in Tidal Restoration...9 Culvert Replacement Benefits •Improve tidal flushing to the marsh –Improve salt marsh, reduce Phragmites –Improve quality of fishery

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